Never in my life have I crimped so much cable as in this test. It would seem that I will always remember the color sequence, repeating it over and over again as a spell: “orange with a strip, orange, green with a strip, blue…”.
Very often, when implementing video surveillance at the facility, the integrator faces the task of placing the camera in a place where there is no power supply, and accordingly, you will not put a repeater there. It can be a camera installation on a tree, on a lamppost, under a dome or in a well. It does not matter where, it is important that you have hundreds of meters of cable to the nearest point in the network, and there is no possibility to put a switch or an extension cord.
Typically, IP surveillance cameras use a 100-megabit or 1-Gigabit twisted-pair connection (category 5 or 5E cable). On the same cable on the camera often has power (PoE), and like it or not, but both technologies (signal transmission and transmission power) is limited by the distance of 100 meters, and now even the forehead knock you yourself will not give you 100 megabits over twisted pair 5th category at a distance of more than 100 meters. The fact is that progress in network equipment is moving towards increasing speeds and reducing energy consumption, and for everything else there is optics. So even if you transmit power at a distance of 200 meters, the signal on the twisted pair will not pass.
And here networkers remembered that at the time when our grandfathers on foot under a table went, there was such standard as 10 Base-T with a speed of only 10 Mbit/s and if to conjure, then on a good cable this network can be thrown further than on 100 meters.
Okay, I have two questions. I do not doubt at all that the power can be transmitted over a copper cable for kilometer distances: this is not surprising: industrial PoE injectors transmit 14 W via cat 5E cable for 700 meters (802.3 at standard) or 450 meters (802.3 af standard). Interest me: